@@ -1,9 +1,9 @@
 'use strict';
 
 function foo(func) {
-  // What to do here?
-  // Replace this comment and the next line with your code
-  console.log(func);
+  console.log('Hello, I am foo!');
+  // The is a call to bar function.
+  func();
 }
 
 function bar() {
 
@@ -2,19 +2,30 @@
 
 function threeFive(startIndex, stopIndex, threeCallback, fiveCallback) {
   const numbers = [];
+  for (let i = startIndex; i <= stopIndex; i++) {
+    numbers.push(i);
+  }
 
-  // Replace this comment and the next line with your code
-  console.log(startIndex, stopIndex, threeCallback, fiveCallback, numbers);
+  for (let j = startIndex; j <= stopIndex; j++) {
+    if (j % 3 === 0 && j % 5 === 0) {
+      threeCallback(j);
+      fiveCallback(j);
+    } else if (j % 3 === 0) {
+      threeCallback(j);
+    } else if (j % 5 === 0) {
+      fiveCallback(j);
+    }
+  }
 }
 
 function sayThree(number) {
   // Replace this comment and the next line with your code
-  console.log(number);
+  console.log(number + ' is devisable by three');
 }
 
 function sayFive(number) {
   // Replace this comment and the next line with your code
-  console.log(number);
+  console.log(number + ' is devisable by five');
 }
 
 threeFive(10, 15, sayThree, sayFive);
 
@@ -4,10 +4,9 @@
 function repeatStringNumTimesWithFor(str, num) {
   // eslint-disable-next-line prefer-const
   let result = '';
-
-  // Replace this comment and the next line with your code
-  console.log(str, num, result);
-
+  for (let i = num; i > 0; i--) {
+    result += str;
+  }
   return result;
 }
 
@@ -17,10 +16,10 @@ console.log('for', repeatStringNumTimesWithFor('abc', 3));
 function repeatStringNumTimesWithWhile(str, num) {
   // eslint-disable-next-line prefer-const
   let result = '';
-
-  // Replace this comment and the next line with your code
-  console.log(str, num, result);
-
+  while (num > 0) {
+    result += str;
+    num--;
+  }
   return result;
 }
 
@@ -31,8 +30,13 @@ function repeatStringNumTimesWithDoWhile(str, num) {
   // eslint-disable-next-line prefer-const
   let result = '';
 
-  // Replace this comment and the next line with your code
-  console.log(str, num, result);
+  do {
+    if (num > 0) {
+      result += str;
+    }
+
+    num--;
+  } while (num > 0);
 
   return result;
 }
 
@@ -1,7 +1,9 @@
 'use strict';
 
 function Dog() {
-  // add your code here
+  this.name = 'Cha';
+  this.color = 'blue';
+  this.numLegs = 2;
 }
 
 const hound = new Dog();
 
@@ -4,8 +4,13 @@ function multiplyAll(arr) {
   // eslint-disable-next-line
   let product = 1;
 
-  // Replace this comment and the next line with your code
-  console.log(arr, product);
+  for (let i = 0; i < arr.length; i++) {
+    for (let j = 0; j < arr[i].length; j++) {
+      product = product * arr[i][j];
+    }
+
+    return product;
+  }
 
   return product;
 }
 
@@ -4,13 +4,25 @@ const arr2d = [[1, 2], [3, 4], [5, 6]];
 const arr3d = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]];
 
 function flattenArray2d(arr) {
-  // Replace this comment and the next line with your code
-  console.log(arr);
+  const flattArr2 = [];
+  for (let i = 0; i < arr.length; i++) {
+    for (let j = 0; j < arr[i].length; j++) {
+      flattArr2.push(arr[i][j]);
+    }
+  }
+  return flattArr2;
 }
 
 function flattenArray3d(arr) {
-  // Replace this comment and the next line with your code
-  console.log(arr);
+  const flattArr3 = [];
+  for (let i = 0; i < arr.length; i++) {
+    for (let j = 0; j < arr[i].length; j++) {
+      for (let k = 0; k < arr[j].length; k++) {
+        flattArr3.push(arr[i][j][k]);
+      }
+    }
+  }
+  return flattArr3;
 }
 
 console.log(flattenArray2d(arr2d)); // -> [1, 2, 3, 4, 5, 6]
 
@@ -20,4 +20,9 @@ f2(y);
 
 console.log(y);
 
-// Add your explanation as a comment here
+// The reason for printing different result  here is the way the variables are used like
+// In first function the value 9 is passed by value so changing the value inside the function.
+// mean val parameter just copied the value of x and used in the function and did nothing to actual value.
+// In 2nd function the the value to y is passed which is an object and objects are passed by reference so any change to val in the function will change y too.
+// because in case of passed by reference val didn't copy the value of y but one can say that after passing by reference here val and y both have the same
+// value {x:9} not copied value like passed by value and any change to one of these will have impact on other that is what caused the change in the value of y.
@@ -3,8 +3,8 @@
 const values = ['a', 'b', 'c', 'd', 'a', 'e', 'f', 'c'];
 
 function makeUnique(arr) {
-  // Replace this comment and the next line with your code
-  console.log(arr);
+  const result = arr.filter((i, j) => arr.indexOf(i) === j);
+  return result;
 }
 
 const uniqueValues = makeUnique(values);
 
@@ -1,8 +1,9 @@
 'use strict';
 
 function createBase(base) {
-  // Replace this comment and the next line with your code
-  console.log(base);
+  return function(x) {
+    return base + x;
+  };
 }
 
 const addSix = createBase(6);
Original file line number	Diff line number	Diff line change
`@@ -1,7 +1,9 @@`
`1`	`1`	`'use strict';`
`2`	`2`
`3`	`3`	`function Dog() {`
`4`		`- // add your code here`
	`4`	`+ this.name = 'Cha';`
	`5`	`+ this.color = 'blue';`
	`6`	`+ this.numLegs = 2;`
`5`	`7`	`}`
`6`	`8`
`7`	`9`	`const hound = new Dog();`
Original file line number	Diff line number	Diff line change
`@@ -3,8 +3,8 @@`
`3`	`3`	`const values = ['a', 'b', 'c', 'd', 'a', 'e', 'f', 'c'];`
`4`	`4`
`5`	`5`	`function makeUnique(arr) {`
`6`		`- // Replace this comment and the next line with your code`
`7`		`- console.log(arr);`
	`6`	`+ const result = arr.filter((i, j) => arr.indexOf(i) === j);`
	`7`	`+ return result;`
`8`	`8`	`}`
`9`	`9`
`10`	`10`	`const uniqueValues = makeUnique(values);`